Failures of MOSFETs in terrestrial power electronics due to single event burnout

Failures of semiconductor devices caused by cosmic radiation exposure is well known in space and avionics applications. However it is not well known that similar issues exist, to a lesser extent, for terrestrial applications. We have conducted research into the phenomenon of single event burnout (SEB) of high voltage power electronics semiconductor devices, specifically MOSFETs that are ubiquitously used in modern switchmode power electronics. The research revealed that SEB and related effects, caused by high-energy neutrons generated by the impact of cosmic radiation on our upper atmosphere, are a real possibility at ground level. An introduction and overview of the SEB effect, a review of existing literature indicating the flux and energy distribution of neutrons that reach the earth's surface and an overview of the structure of MOSFET devices indicating why they could be susceptible to the SEB effect is given. Experiments were conducted which demonstrated that random failures of high voltage MOSFET devices, when they are biased in the off state, do occur at a much higher rate than should otherwise be expected. A summary of experiments that were carried out at the TRIUMF cyclotron laboratory on both individual MOSFETs and on electronic equipment containing MOSFETs is presented. These experiments provide strong evidence that failures of MOSFETs and circuits using MOSFETs can be caused by neutrons with energy distributions similar to that experienced on the earth's surface.